Macular degeneration

• Age-related macular degeneration:

  • Progressive loss of central vision
  • Formation of drusen and changes in the retinal pigmentary epithelium
  • Primary associated with ageing
  • Most common cause of blindness in people over 60
• Risk factors include:

  • Age
  • Ethnicity (more common in Caucasian individuals)
  • Family history
  • Smoking
  • Hypertension
  • Diet (high fat intake)
  • Drugs (e.g. aspirin)
  • Other (sunlight exposure, blue eyes, female>male, previous cataract surgery)
• Dry AMD:

  • 90% of all AMD
  • Non-exudative and non-neovascular
  • Asymptomatic drusen formation in Bruch's membrane
  • Drusen are small yellowish deposits visible on fundoscopy
  • Advanced - pigmentary changes and geographic atrophy
  • Visual deterioration is usually slow
• Wet/neovascular AMD:

  • Formation of choroidal neovascular membrane made up new, aberrant blood vessels underneath the retina
  • Driven by vascular endothelial growth factor
  • More rapidly progressive loss of vision
  • Exudate from the new, leaky vessels or by haemorrhage
• History:

  • Progressive, central vision loss
• Symptoms:

  • Central vision loss
  • If very acute - more likely to be wet AMD and is ocular emergency
  • Symptoms often exacerbated by low light conditions
  • AMD can affect both eyes but usually unilateral
• Common examination findings include:

  • Visual field assessment – central scotoma (loss of the central vision)
  • Amsler grid – central metamorphopsia (loss of linearity in the grid centrally)
  • Fundoscopy, using a hand-held ophthalmoscope/slit lamp – visualisation of drusen/choroidal neovascular membrane/geographic atrophy
• Imaging:

  • Ocular coherence tomography - high resolution imaging of the retina
  • Fluorescein angiography
  • Indocyanine green angiography
  • Autofluorescent imaging
• An Amsler grid should also be provided to patients so that they can regularly assess their vision at home
• All providers should discuss any treatable risk factors with patients, including smoking, ocular sun exposure, cardiovascular health and diet.
• Referral to ophthalmology is recommended at any point in the disease process, even if visual acuity is normal. Urgent referral within 2 weeks is warranted if wet AMD is suspected, as treatment should be started promptly to preserve sigh
• Dry AMD management:

  • Low vision refractory aids may be helpful early on
  • Some proven benefit in providing vitamin supplements:
  • Exogenous antioxidants
  • Vitamin C and E
  • beta-carotene
  • Zinc
  • macular pigments
  • Lutein
  • Zeaxanthin
• Wet AMD management:

  • Intravitreal anti-VEGF therapy e.g. Aflibercept and ranibizumab
  • usually given monthly for three months
• Other management strategies:

  • Registration with the national centre for the blind
  • Regular eyesight testing and notification to the road safety authority*
  • Social work involvement
  • Occupational therapy
  • Psychology involvement in cases of adjustment/mood disorder.
• Most people with AMD are still able to drive if their visual acuity with both eyes open is 6/12 or better (the Snellen chart equivalent of reading a car number plate at 20 meters). Failure to meet this standard requires the patient to inform the DVLA and stop driving.